Montracon Ltd v Whalley

This is an appeal from the judgment and order of His Honour Judge Moore sitting at Sheffield County Court on 29^th October 2004. The judge made an award of damages of £21,000 with £840 interest in favour of the claimant, Gregory Whalley, the respondent to this appeal, who had alleged that he was suffering from hand arm vibration syndrome as the result of prolonged use of vibrating tools during the course of his employment with the defendant, Montracon Ltd. Montracon Ltd now appeals against that order with the permission of Pill LJ.

The appellant manufactures trailers for heavy goods vehicles at its factory at Balby, near Doncaster. The respondent worked in the shell bay of these premises. His claim was one of ten similar claims brought by the appellant’s employees, all alleging that they had developed hand arm vibration syndrome (HAVS) as the result of the prolonged use of vibrating tools. The claims were not strictly-speaking test cases but it was the intention of the parties that all the issues relating to the use of vibrating tools and the effect upon the workforce would be ventilated in the course of the hearing and that the judgment would help the parties to deal with a substantial number of other similar cases without resort to the courts. For various reasons, only six cases remained for decision at the end of the hearing.

The judge found in favour of the appellant in three of the six cases, on the basis that the claimants in those cases had failed to prove that they were probably suffering from HAVS or any condition that could be attributed to their use of vibrating tools. In those cases in which the diagnosis was made out, the judge found that, from 1991, the appellant should have been aware of the adverse effects of the prolonged use of vibrating tools used at its premises and should have taken steps to warn their employees of that risk, to provide periodic medical examinations and to take measures to reduce the extent of their exposure. The appellant had failed to take any of these steps. Any claimant who could show prolonged usage of vibrating tools since 1991 and who could demonstrate that he had HAVS would succeed.

In respect of the respondent, Mr Whalley, who had been employed by the appellant since 1993, the judge found that, for about five years after the start of his employment, he was exposed to level of vibration of at least 3.6 m/s². That is a level at which a risk of developing HAVS would arise. He had not been exposed to any vibration before joining the appellant. Since 1999, his vibration exposure had reduced although he was still exposed. The real issue in the case was whether the respondent was suffering from HAVS. The judge found that he was and it is in respect of that finding alone that this appeal is brought.

HAVS is a complex manifestation of physical damage caused by the prolonged use of vibrating tools. It was first observed over 100 years ago, when it was reported that men using vibrating tools for many years developed a form of gangrene of the finger tips. That was an extreme form of the condition. Far more commonly, the workman’s fingers would, episodically, go white and feel numb. After a while, they would regain their usual colour and feeling would return. This process would be accompanied by a tingling sensation like pins and needles. The condition became known as vibration white finger (VWF). It was also known as Raynaud’s Phenomenon, after the doctor who had first described episodic finger blanching of constitutional origin. White finger episodes are understood to be caused by temporary interference with the blood supply to the fingers due to vasospasm. However, in recent years, it has been realised that the effects of vibration are rather more complex than had hitherto been thought. It is now accepted that, in addition to episodes of white finger, vibration can cause damage to the nerves in the fingers; this is known as the sensorineural effect. Such damage gives rise to tingling and pins and needles and also to loss of dexterity, continuously not episodically. It is also accepted that vibration can cause musculo-skeletal problems, such as loss of grip. Because of these various manifestations, the condition is now called HAVS rather than VWF. The term VWF is now applied only to the vascular component of HAVS, the episodic whitening of the fingers. Doctors examining a patient or claimant will look for evidence of the various possible components, which may be present in any combination.

In order to introduce an element of consistency of description of the symptoms of HAVS, doctors specialising in the condition have devised two different scales by which the severity of the condition can be described. These are the Taylor Pelmear Scale, which deals only with the vascular symptoms and the Stockholm Workshop Scale which deals with vascular and sensorineural effects. It is not necessary for the purposes of this judgment to explain the operation of the scales in detail.

The diagnosis of HAVS often gives rise to difficulty. There are several reasons for this. The first is that it is very rare indeed for a patient or claimant to suffer an attack during the course of a medical examination. Episodic attacks of finger blanching are precipitated by cold and do not usually occur in the warm environment of a consulting room. Unfortunately, there is no test which can prove whether or not a claimant does in fact suffer from these intermittent episodic symptoms. The doctor is dependent upon the patient’s or claimant’s description of his symptoms. This in turn is dependent upon the perception of the claimant and his use of language.

Difficulties of diagnosis are compounded by the variability of the manifestations of the vibration-induced condition. As I have said, there may be more than one component of HAVS present in the same person. Even with the vascular symptoms alone, there is no history of onset which can be regarded as typical to the extent that it is diagnostic. Symptoms of the vibration-induced condition do not begin to manifest themselves for several years after exposure begins. That latent period varies greatly not only according to the severity of the exposure but also according to the personal susceptibility of the workman. Indeed, some workmen are exposed to very severe vibration for many years and do not develop symptoms at all. Others can develop symptoms after only a few years’ exposure. In general, it can be said that young people are more vulnerable to developing the condition than older ones, women are more vulnerable than men and people who are light in weight are more vulnerable than those with a heavy frame.

Another difficulty arises because vascular symptoms of episodic whiteness and numbness, virtually indistinguishable from the vascular symptoms caused by exposure to vibration, occur naturally in about in about 5% of men and 15% of women in the general population. Unfortunately, there is no clear way in which the occupational condition can be distinguished from a natural occurrence, although a history that the condition was first noticed in those fingers in closest contact with the vibrating tools will tend to support a diagnosis of the vibration-induced condition. Thus, the terminal phalanges of the index and middle fingers of the dominant hand may well be affected first. Over a period of time, the condition may spread to other fingers and further up the fingers. It may spread to the non-dominant hand and eventually affect even the thumbs. In general, the constitutional condition affects all the fingers of both hands equally. However, this difference is by no means diagnostic. Vibration can cause bilateral symptoms from the start.

There are also difficulties in attributing sensorineural and musculoskeletal symptoms to vibration as these symptoms can occur naturally as the result of all manner of constitutional conditions. Accordingly, for all these reasons, diagnosis of the occupational condition is difficult. It depends upon three factors: first a history of exposure to vibration sufficient to cause a risk of development of the condition; second, a clinical history and description of symptoms which is consistent with one or more of the components of HAVS; and third, the absence of any constitutional explanation for the symptoms complained of.

Yet further difficulties of diagnosis have arisen in recent years because it has become well known among groups of working men that compensation is available for HAVS. Rightly or wrongly, the insurance industry believes that it is faced with many fraudulent claims made by workmen who do not have the condition at all but who have learned from others what the symptoms are and how to give a convincing account. Doctors examining such claimants seek to be astute to such deception. They consider that, although a deceitful claimant might have learned most of what he should say, he does not know all the answers and might be revealed as false if questioned closely about his symptoms. Any facet of the description which does not tally with what is expected may lead the doctor to conclude that the claimant is fabricating his symptoms. In this group of cases, the employers were deeply suspicious of the truthfulness of all the claimants. All claimants were questioned very closely by the doctors at examination and by counsel during the trial about the appearance of their hands during an attack and about the ways in which they claimed that the condition affected their daily lives.

The respondent said that he had first experienced symptoms in about 1996. He had noticed that the terminal phalanges of the index and middle fingers of the right dominant hand turned numb and went white. Over the course of about six months, the condition spread to the proximal inter-phalangeal joint and other fingers became affected. The episodes of finger whitening became quite frequent; they were provoked by cold. When an attack began, the respondent would try to put his hands into hot water; if he did, the symptoms would subside after only a few minutes. If he could not, for example because he was out for a walk, they might last for up to an hour. When an attack was subsiding, he would notice a blue colour and experience tingling like pins and needles. He also said that he had some tingling during and immediately after using the tools. He also claimed to have some loss of fine dexterity; he thought he was clumsy when attempting fine movements. He had given up golf because his grip was affected and had stopped fishing because he tended to get attacks when his hands were wet and also he had difficulty handling hooks and lines. In the last year or two, the condition had spread to his thumbs.

The respondent was cross-examined very closely for a substantial period. Virtually every aspect of the evidence was challenged as untrue. In particular, it was put to him that he had heard about the availability of damages and had learned how to describe his symptoms, probably from his father who had apparently made a claim for HAVS; if not from him, then from others. In general, the thrust of the cross-examination was that he had learned his lines. However, at one stage, counsel focussed upon the fact that, when giving evidence in chief, the respondent had, for the first time, said that his fingers went blotchy at the start of an attack of white finger. He had explained that, as soon as an attack began, he would try to put his hands into hot water. He was asked to describe what happened to make him think that an attack was coming on. He said:

The respondent had been examined by a number of doctors. In 2000, he had seen an occupational physician named Dr R Swann. Dr Swann did not give evidence although his reports were before the Court. He had concluded that the respondent had HAVS and opined that, on the Stockholm Workshop scale, he had vascular symptoms at stage 2 and sensorineural symptoms at stage 3. That would suggest symptoms of moderately severe degree. Following the commencement of proceedings in 2002, the respondent’s solicitors instructed Mr Morris-Jones, a consultant vascular surgeon and the appellant instructed Dr Roger Cooke, an occupational physician. Following their examination of the respondent, the doctors disagreed as to the diagnosis. Mr Morris-Jones concluded that the respondent had HAVS; he was suffering from a moderately severe degree of the vascular component (assessed at borderline stage 2 to 3 on the Stockholm Scale) but no sensorineural or musculoskeletal elements.

Dr Cooke was of the view that the respondent did not have HAVS at all. He did not say in terms that he regarded the respondent as a liar but that was the implication behind his opinion. His opinion was based mainly upon his understanding that the respondent had told him that, during a vascular attack, his fingers went white at the tips and the colour ‘faded’ gradually along the length of the fingers. That was a description which could not apply to HAVS. The white finger symptoms are caused by a temporary blockage of the blood vessels and, during an attack, there is a clear demarcation line between the white parts of the fingers and the rest, which are unaffected.

Before the hearing, the two doctors recorded their agreement that their difference of opinion was based upon the different descriptions each had recorded as having been given by the respondent during consultation. Mr Morris-Jones had recorded that when the respondent’s fingers went white, there was a clear demarcation of colour horizontally across the fingers. That was typical of the vascular element of HAVS. As I have said, Dr Cooke had recorded that the colour ‘faded’ along the finger and had concluded that this was inconsistent with HAVS. However, when giving evidence, the respondent had told the judge that Dr Cooke must have misunderstood his description of the white areas on his fingers. He had always said that there was a clear demarcation between the white affected areas and the pink normal areas.

At the hearing, the medical evidence took an unusual turn. As soon as Mr Morris-Jones went into the witness box, he told the judge that he wished to change his opinion on the case. He said that he had heard the respondent’s evidence the day before (when he had first described his hands as blotchy at the onset of an attack) and his further evidence that morning, when he had been cross-examined about blotchiness. This had made him change his mind. He said that, in his view, a blotchy appearance during the onset of an attack was inconsistent with a diagnosis of HAVS. He mentioned that Pelmear (a leading expert on HAVS, whose textbook was included in the bibliography attached to the joint report on generic issues prepared by Mr Morris-Jones and Dr Cooke) accepted blotchiness as consistent with HAVS. However, he said that he personally had never accepted it. It was difficult, he said, to see how, physiologically, it could happen. He agreed that one should always give some latitude to the descriptions given by patients because of their descriptive abilities. He agreed that one did not always hear a classical description even in genuine cases. But he said that he had been ‘shaken’ when the respondent had described blotchiness. He had not used that description on the previous occasions when he had described his symptoms. Mr Morris-Jones accepted that, save for that one aspect of his evidence, the respondent had given a very good history and a description of symptoms entirely consistent with HAVS; but, he said, the description of blotchiness during the onset of an attack was sufficient to undermine the whole of the rest of the evidence. Mr Morris-Jones no longer thought that the respondent had HAVS.

All this emerged during evidence-in-chief and it was repeated in cross-examination. In due course, Miss Foster, counsel for the appellant, asked Mr Morris-Jones if he would like to leave the court so that he could ‘consider his position’. He accepted. The two doctors then conferred, with the permission of both counsel. They produced a joint agreed report, the effect of which was that the doctors were of the view that the respondent did not have HAVS. As a rider to their medical opinion, the doctors added:

When the doctors had produced this agreed report, Miss Foster submitted to the judge that the medical issue had now been conclusively determined in the appellant’s favour. Mr Mallett disagreed, submitting that the joint report was based upon the doctors’ understanding of what the respondent had said in evidence and the inferences that might be drawn from an apparent change in his evidence. Those were matters for the judge to assess, after hearing all the evidence. The judge agreed and the evidence was resumed.

Dr Cooke was asked first about the respondent’s use of the word blotchy. He agreed with Mr Morris-Jones that the description of a stage of blotchiness when the colour was disappearing from the fingers at the start of a vascular attack was inconsistent with HAVS. His reasons for so saying were similar to those given by Mr Morris-Jones. He did not mention Pelmear’s dissenting view. He said that he had other reservations about the history and description given by the respondent which had caused him to conclude previously that the respondent did not have HAVS. The description of blotchiness was another reason which reinforced his opinion.

He was then asked about this first reservation, which related to the question of whether the colour change was well demarcated or whether it faded along the length of the finger. Dr Cooke said that he had questioned the respondent closely about the supposed fading of the colour and had specifically asked him whether he meant fading along the length of the finger. He said that he asked the respondent whether the appearance of his hands was as if he had dipped his fingers into a pot of paint; the respondent had said no. He said that that was a question he always asked. However, it was clear that Dr Cooke had not made any contemporaneous record of this question and answer. In his judgment, the judge noted that, in the course of a long and careful cross-examination by Miss Foster, it had not been suggested that Dr Cooke had asked the respondent whether the appearance of his fingers was as if they had been dipped into a pot of paint. In his judgment, on this issue, the judge rejected Dr Cooke’s evidence and accepted that the respondent had always described the appearance of his fingers as having a clear demarcation of colour during an attack.

The judge accepted the respondent’s evidence as truthful and accurate. He had not been influenced by any outside agency, be it his father or anyone else. He had given a very clear account of his symptoms. The judge concluded that, save for the evidence about blotchiness, everything pointed to the conclusion that the respondent suffered from the vascular component of HAVS. The judge then reviewed the evidence relating to blotchiness and said:

After handing down his judgment, the judge refused permission to appeal. In so doing, he reiterated his reasons for rejecting the doctors’ opinions by saying:

In this appeal it was submitted by Mr Waite QC for the appellant, first, that the judge had erred in rejecting the agreed medical evidence as to diagnosis. It was not open to him to do so. In rejecting the doctors’ opinions and in substituting his own view, he was usurping the position of the medical experts.

Second, it was submitted that the judge was wrong to say that the doctors had misunderstood the respondent’s evidence. The judge said that the doctors had thought that the respondent had been describing the appearance of his hands after the vasospasm had started whereas, in the judge’s view, he had been speaking of the time when he first became aware of a sensation in his hands and looked at them before the vasospasm had properly begun. Mr Waite referred us to passages of the transcript from which he invited us to infer that the doctors had perfectly well understood that the respondent had been saying that he saw the blotchiness right at the beginning of, or indeed just prior to, the attack.

Third, it was submitted that the judge’s record of the evidence on which he had relied in rejecting the doctors’ opinion was inaccurate. It did not tally with the transcript of the evidence. Where, in paragraph 91, the judge had referred back to paragraph 7 of the judgment, he had meant to refer to paragraph 77. In that paragraph, he had quoted, apparently from his own note, that the respondent had said:

Mr Mallett for the respondent submitted that the judge had not usurped the doctors’ function. It was apparent that what lay behind Mr Morris-Jones’s change of evidence and Dr Cooke’s view of the respondent was their belief that he was not telling the truth. One could see that from the rider they had added at the end of their final joint report. They had recognised that issues of credibility were matters for the judge but, nonetheless, they had felt it appropriate to add that they were concerned about the change in the respondent’s evidence. They were giving the judge a clear hint that they thought the respondent was lying. But whether he was lying was a matter for the judge. He was satisfied that the respondent was an honest witness and made his findings on that basis. In those circumstances, the judge was entitled, even bound, to examine the doctors’ opinions closely and was entitled to reject them if he regarded them as untenable, unreliable or based upon a misapprehension of the evidence.

As for the second and third points, which are closely related, Mr Mallett submitted that the judge was in the best position to interpret what the respondent had said.

I for my part accept Mr Mallett’s submission that the judge was not bound to accept the experts’ opinion. All issues of credibility are for the judge. Also, if what a witness has said is ambiguous or its interpretation is in doubt, it is for the judge to decide upon the correct interpretation. Such a decision by the judge would only be open to challenge on appeal if it can be shown that the judge had misheard the evidence.

Here it does appear to me that the judge has misheard at least part of the evidence. There is a difference between what the judge noted down and reproduced at paragraph 77 of the judgment and what the respondent actually said, as recorded in the transcript. The respondent had not said that his hands went white ‘straightaway’ after he looked at them; instead he had said that, when an attack started, he went to find a hot tap ‘straightaway’. However, it does not seem to me that that difference is of any real significance. The fact that the respondent did not use the word straightaway when describing the change in the colour of his hands does not mean that the judge’s interpretation of his description of the appearance of his hands was wrong.

More important is whether the judge was justified in interpreting the respondent’s evidence as he did, differently from the doctors. It was clear from the transcript that the doctors had understood that the respondent was saying that his hands changed from their normal appearance to a blotchy appearance at the start of an attack but as part of that process. Mr Mallett had suggested to them that the respondent could have looked at his hands, as soon as he realised from the sensation that a change was beginning. They would then have a blotchy appearance because most people’s hands are normally blotchy. He would then see them change to white as the blood drained out. Mr Morris-Jones’s evidence on this point was that if the respondent was saying that, as the attack was starting, he looked at his hands and his fingers changed from their normal appearance to blotchy, that would be inconsistent with a diagnosis of HAVS. However, if what the respondent had meant was that when he first became aware that an attack was about to start, he looked at his hands and they had their normal blotchy appearance which then changed to white as the blood drained out, that would be possible and not inconsistent with HAVS. Dr Cooke also accepted that the hands might have a natural appearance of blotchiness before the attack began but said that that would be nothing to do with an attack of white finger. He said that he understood that the respondent was associating the blotchiness with the start of an attack but was saying that it was a change that was part of the process of the attack.

The real question is what had the respondent said about the blotchiness of his hands? It seems to me that his evidence on this point was somewhat ambiguous. At times he appeared to describe a change in the appearance of his hands from normal to blotchy and then to white but at times he seemed to be saying that when he looked at his hands, they were blotchy and then they changed to white. Looking at the respondent’s evidence as a whole, I can well understand why the doctors understood the evidence as they did. Having said that, interpretation of the evidence is primarily a matter for the judge, who was able to see the witness and hear the way he spoke, how he paused, whether he was repeating himself or going back on himself. It was for the judge to interpret what the respondent actually meant by his words, where the meaning was not entirely clear. I consider that the judge was entitled to take the view that, when the respondent said that his hands were blotchy, he was describing their appearance before any changes due to the attack had begun. On that interpretation of his evidence, the judge was entitled to say that the blotchy appearance was not inconsistent with the diagnosis of HAVS. That is what the doctors had agreed.

I would therefore reject Mr Waite’s submission that the judge had not been entitled to reject the doctors’ interpretation of the evidence. Accordingly, I would dismiss the appeal. However, even if the judge had not been entitled to interpret the respondent’s evidence as he did, I would not have allowed this appeal. The judge was satisfied that the respondent was honest and genuinely suffered from the symptoms he had described. He had not learned what to say from others. He had not been jumping on the compensation bandwagon, as the appellant had contended. Save for the description of blotchiness, the respondent had given a ‘textbook’ account of the vascular component of HAVS. The medical examination had revealed no constitutional condition that might explain his symptoms. Moreover the engineering evidence was that the respondent’s vibration exposure had created a risk of HAVS. The evidential jigsaw was complete save for one piece which did not apparently fit.

It seems to me that even if there were no explanation for that ill-fitting piece of evidence, the judge was entitled to say that he was satisfied, on the balance of probabilities, that the respondent was suffering from HAVS. Where the civil standard of proof applies, it is not necessary for every piece of the evidential jigsaw to fit. To require that is to apply too high a standard of proof. In any event, there were at least two possible explanations for the ill-fitting piece of evidence besides the explanation adopted by the judge. One was that the respondent had accurately described the changes to his hands as going from normal to blotchy to white and that Mr Morris-Jones and Dr Cooke were wrong when they said that this absolutely ruled out a diagnosis of HAVS. Mr Morris-Jones had mentioned that Pelmear was prepared to accept that a blotchy appearance did sometimes appear at the start of a vascular attack. Pelmear is a highly reputable expert in this field of medicine. Mr Waite submitted to us that Pelmear’s opinion was not in evidence before the court; the judge could only act upon the evidence of Mr Morris-Jones and Dr Cooke. I cannot accept that submission. Mr Morris-Jones’s evidence was that at least one reputable doctor did not agree with his opinion. It would, in my view, have been open to the judge to say that a possible explanation for the evidence of blotchiness was that the respondent had an unusual presentation of symptoms. Mr Morris-Jones himself had accepted that sometimes unusual presentations did occur. Another possible explanation was that the respondent had not described the appearance of his hands clearly or accurately. The doctors had accepted that patients and claimants often had difficulty in describing their symptoms and agreed that allowance had to be made for that.

I would dismiss this appeal because I consider that the judge was entitled to reject the doctors’ evidence for the reasons that he gave for so doing. However, even if the judge’s reasoning had been faulty, I would still dismiss the appeal because the judge was entitled to find in the respondent’s favour, on the balance of probabilities, on the totality of the evidence before him, even though that evidence contained one element which pointed against the judge’s conclusion.

For all the reasons which my Lady has given, I agree that the appeal should be dismissed. But it may just be worthwhile to add a footnote about the different forensic dynamics in play in this court from those in play before the judge. As my Lady has observed, the respondent’s evidence led Mr Morris-Jones to agree with Dr Cooke that he was not telling the truth; and they gave the judge a clear steer in that direction. Such also was the foundation of Miss Foster’s final submission to him. The judge, however, firmly found that the respondent was telling the truth; and Mr Waite realistically concedes that in this court he cannot challenge that finding. In this court, therefore, we proceed on the footing that the respondent’s account was true. This, so it seems to me, greatly reduces the capacity even of Mr Waite to object to the judge’s rejection of the medical evidence. Mr Waite is constrained to argue not that the respondent was not suffering from a condition but that his condition should not have been found to be HAVS. Quite apart from whether there would be ultimate value for him in establishing it, his argument raises the question: if the respondent’s condition was not HAVS, what on earth was it? In the light of their different thesis the question was of course unanswered by the doctors; and there is nothing to indicate that it is answerable at all.

I agree that this appeal should be dismissed. In reaching that conclusion I have obtained great assistance from the illuminating explanation of the difficulties of diagnosis in HAVS cases, so helpfully set out by Lady Justice Smith in her judgment. As she points out, diagnosis in these cases is more than usually dependent upon the claimant’s description of his symptoms; and so more than usually dependent on the claimant’s credibility.

Each of the medical experts had examined the claimant in advance of the trial. Dr Cooke had taken the view that the claimant was not to be believed. Mr Morris-Jones had taken the opposite view. Each expert then heard the claimant give his evidence at the trial. It was as a result of what he understood the claimant to be saying in the course of his evidence that Mr Morris-Jones altered his view. He understood the claimant to be describing, for the first time, a symptom (blotchiness during the onset of the attack) which, in his opinion, was wholly inconsistent with HAVS. That led him to the conclusion that he could no longer rely on anything that the claimant had said about his symptoms – either in advance of the trial or in the course of his evidence. It is clear from the rider to the joint memorandum which the two doctors agreed after hearing the claimant give his evidence that they thought that he was not to be believed.

Whether the claimant was to be believed at the trial was not a question for the doctors: it was a question for the judge. The judge found the claimant to be a credible witness. He reached that conclusion after hearing the claimant’s evidence tested by a careful and searching cross-examination. There is no basis upon which that conclusion can be challenged in this Court.

The question, then, is whether – given that he accepted that the claimant’s account of his symptoms was true and accurate – the judge was entitled to conclude that the claimant was suffering from HAVS. The agreed joint memorandum gives little or no assistance on that question; because the doctors did not accept that the claimant’s account of his symptoms was true and accurate. But, as Lady Justice Smith has explained, there was material upon which the judge could have reached the conclusion that he did. All the symptoms described by the claimant – with the exception of blotchiness during the onset of the attack – were consistent with HAVS. Although Mr Morris-Jones thought that the blotchiness was not consistent with HAVS, he had to accept that a contrary view had been expressed by a leading authority (Pelmear). And he had to accept that an unusual presentation of symptoms could not be ruled out. The judge had to take the evidence as a whole. Having accepted that the claimant had given a true and accurate account of his symptoms, he was entitled to reach the conclusion, on the balance of probabilities, that the claimant was suffering from HAVS.